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e vassar 08-12-2019 11:34 AM
Alternator question
 
For a stocker (LS Camaro) running BS3 elec fan,water pump,fuel pump, lights at night. Typical race car...what would be the smallest amp alternator I should run?...thks

Hacksaw 08-12-2019 11:47 AM
Re: Alternator question
 
Be careful here. A alternator needs to spin about 2500 rpm or more before it starts to break even and produce + current.

cmracing 08-12-2019 10:07 PM
Re: Alternator question
 
100 amps minimum.

bigfoot584 08-13-2019 04:00 PM
Re: Alternator question
 
Quote:
Originally Posted by Hacksaw (Post 594403)
Be careful here. A alternator needs to spin about 2500 rpm or more before it starts to break even and produce + current.

Engine rpm's ? or actual alternater rpm's ?


Big difference.

Hacksaw 08-13-2019 05:33 PM
Re: Alternator question
 
Quote:
Originally Posted by bigfoot584 (Post 594472)
Engine rpm's ? or actual alternater rpm's ?


Big difference.
Just checked with an old guy who was a rebuilder and had a test bench. From memory he says about 1800 alt. rpm before they began to produce + current. So on a normal pkg. the ratio of crank to alt. pulley is approx. 3 to 1, which means at idle your not producing current back into the battery. Now with a smaller race crank and larger race alt. pulley to avoid spinning the alt. to the moon it's probably 1100 or 1200 rpm. Also they eat up at least 3 hp, maybe more.


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